Renesas 71V321L55PFI

Overview

71V321L55PFI from Renesas Electronics (formerly IDT) is a high-speed, 3.3V, 2K × 8 dual-port static RAM with on-chip interrupt logic and BUSY arbitration for interprocessor communication. It delivers 55 ns read/write cycle time, supports independent asynchronous access from left/right ports, and features battery-backed data retention down to 2.0 V. It is used in real-time embedded systems requiring concurrent memory access between two processors or DMA engines.

For engineers reviewing the 71V321L55PFI datasheet, 71V321L55PFI pinout, 71V321L55PFI application, or 71V321L55PFI equivalent, this page provides verified technical context, validated pin functions, confirmed timing parameters, industrial-grade thermal specs (–40°C to +85°C), and real-world dual-port memory integration guidance - all specific to the 71V321L55PFI variant in 64-pin TQFP package.

Technical Context

The 71V321L55PFI implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port. Its on-chip arbitration logic uses address and chip-enable matching (not R/W state) to assert BUSYL/BUSYR outputs, enabling hardware-controlled contention resolution without external logic.

Interrupt functionality is implemented via dedicated mailbox addresses: INTL asserts when right port writes to 0x7FE; INTR asserts when left port writes to 0x7FF. Both flags are active-high totem-pole outputs, and clearing requires a read access to the same address with OE and CE asserted.

Key Specifications

Pinout & Package

71V321L55PFI is housed in a 64-pin Thin Quad Flatpack (TQFP, package code PNG64), measuring 10 mm × 10 mm × 1.4 mm. All VCC pins must be decoupled locally; all GND pins require low-impedance ground plane connection.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with CY7C024AV-55AXC and AS7C3256B-55JCIN, the 71V321L55PFI uniquely integrates hardware arbitration and interrupt mailboxes in a compact 64-pin TQFP, reducing BOM count and PCB area while guaranteeing deterministic interprocessor synchronization - critical for industrial safety and avionics systems.

Availability

71V321L55PFI is available at Aetrix Electronics and suitable for industrial PLCs, real-time DSP co-processing, redundant power controllers, avionics data concentrators, and medical imaging subsystems requiring stable component supply and long-term lifecycle support.

Supply support for 71V321L55PFI includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and memory solutions for industrial, automotive, and infrastructure markets.

The 71V321L series was originally developed by Integrated Device Technology (IDT) and acquired by Renesas in 2019; it targets deterministic interprocessor communication in real-time embedded systems requiring hardware-synchronized shared memory.

FAQ

What is the maximum operating temperature range for the 71V321L55PFI?

The 71V321L55PFI is rated for industrial temperature operation from –40°C to +85°C, as confirmed in the Absolute Maximum Ratings and Recommended Operating Conditions tables of the official Renesas datasheet (DSC-3026/14). This rating applies specifically to the 'I' grade suffix in the part number and is validated across all AC and DC electrical parameters at full speed (55 ns).

Does the 71V321L55PFI support true dual-port concurrent read/write operations?

Yes, the 71V321L55PFI supports fully asynchronous, independent read and write operations on left and right ports - provided they target different memory addresses. When both ports access the same address simultaneously, BUSY logic asserts to stall one port, preserving data integrity. This behavior is documented in Truth Table III and Timing Waveform drw 10.

How does the interrupt function work on the 71V321L55PFI?

The 71V321L55PFI uses fixed SRAM addresses 0x7FE (for INTL) and 0x7FF (for INTR) as hardware mailboxes. Writing to 0x7FE from the right port asserts INTL; writing to 0x7FF from the left port asserts INTR. Flags are cleared by reading the same address with OE and CE active - all defined in Truth Table II and Functional Description section.

What is the data retention capability of the 71V321L55PFI?

The 'L' suffix denotes low-power design with guaranteed data retention at VCC ≥ 2.0 V, consuming ≤500 µA (typ. 100 µA) per the Data Retention Characteristics table (3026 tbl 07). This enables reliable backup operation from 2V sources such as lithium coin cells or supercapacitors during main power interruption.

Is the 71V321L55PFI pin-compatible with earlier speed grades like 71V321L25PFI or 71V321L35PFI?

Yes - all 71V321L variants in the same package (e.g., PNG64 TQFP) share identical pinout, voltage levels, and functional interface. The '25', '35', and '55' suffixes denote access time grading only; timing parameters differ, but DC characteristics, pin assignments, and logic behavior are fully compatible per datasheet Section 14 (Ordering Information) and Pin Configurations.